The name is self explanatory. “Vibration damper” is exactly what it does. It dampens or absorbs the torsional vibrations (normal vibrations) caused from the crankshaft. Every time a cylinder fires up the crank rotates; causing all sorts of very technical vibrations which I won’t get into here. The simple solution to this magnitude of force is mounting a big rubber damper or pulley onto the front part of the crank.